1.1 Introduction The principal goal of the Experimental Animal Core is to house mice in the more cost effective and efficient manner in a central facility for all three of the proposed projects. The generation of transgenic mice has proven to be a very powerful tool in answering biologic questions, especially those directly relevant to human disease. However, animal modeling has become increasingly complex with many variables to consider including mouse strain, the selection of tissue specific promoters to modulate targeted gene expression, as well as overall expense. The function of Core B is to serve as a centralized resource to house and maintain the animals and to keep the overall costs of experimental animals to a minimum for the program. In addition. Dr. John Manis will act as a scientific resource to the investigators in planning for the generation of compound mutant mice with multiple genotypes for experimental analysis. Various genetically engineered animals and normal control mouse strains that will be employed in the scientific studies of the program are housed in the core facility, and used during the course of this proposal. Each mouse strain will be housed and generated in direct proportion to the need ofthe investigator, with a breeding and management algorithm using a specialized software based method (Granite).